Properly done, this is a great way to motorise a butty/horse boat. No brutal cutting about of the hull itself. I can say from experience, having briefly owned Capella, that she steers really easily. It's like having a big outboard stern thruster, and as it can direct the thrust beyond 90 deg. the boat can be spun in her own length with no backing and forwarding, also steers beautifully astern, you just point the ellum where you want to go and the boat follows.

And they still look like proper boats (I don't much like the ABC effort, neither fish nor fowl, possibly the worst of both!)